Liquid skin protective composition

ABSTRACT

Provided is a liquid skin protective composition capable of protecting the skin from chemical substances in the environment and aqueous irritants such as body fluids, wastes, and exudates, causing less irritation, being applicable easily to the skin, and giving a good skin feel. The liquid skin protective composition contains the below-described ingredients (A) and (B) and having a water content not more than 10 wt. %: (A) a block copolymer having a linear polysiloxane-polyoxyalkylene block as a structural unit and having an HLB not more than 6, (B) at least one oil selected from mineral oils, vegetable oils, animal oils, synthetic oils and organopolysiloxanes other than the ingredient (A).

TECHNICAL FIELD

The present invention relates to a liquid skin protective composition.More specifically, the invention pertains to a liquid skin protectivecomposition to be used for protecting the skin from any substanceshaving an adverse effect on the skin when the skin comes into contactwith the substances such as chemical substances in the environment,chemical substances in water, allergens, urine, feces, sweat, blood,body fluid, and wound exudate, particularly for protecting the skin at adiapered site of babies or other incontinent individuals, the skinaround stoma and the skin around wound with exudate.

BACKGROUND ART

The surface of the skin is covered with a horny cell layer. Ceramide,lipid, NMF and the like contained in the horny cell layer serve as abarrier against foreign matters from the outside world and they arehighly effective for blocking permeation of these foreign matters. It ishowever known that since the skin, inside of a diaper, of infants orcare receivers using diapers, the skin around stoma or the skin aroundwounds with exudate such as bedsores tend to be in contact for longhours with a high water-content liquid such as sweat, urine, feces,wound exudate or the like, the barrier function of the skin is destroyedand lowered by the action of water, enzymes such as lipase, protease andurease, microorganisms, ammonia generated thereby, or toxins. Fecesexcreted in a diaper stick to the skin. They must be removed byvigorously scrubbing the skin or performing genital washing upon eachdiaper change. Such a behavior increases a care-giver burden and inaddition, repeated genital scrubbing or washing whenever a diaper ischanged damages the skin which has already lowered in resistance andmoreover, increased in friction resistance owing to the influence ofmaceration resulting from the friction of the skin with a towel or paperused for scrubbing or washing. These are said to be causes of diaperrash. They are also said to be causative of bedsores in the bedriddenelderly.

A skin protectant using an alkylsiloxane-containing polymer (forexample, JP-A-4-501076), a skin protectant using an organic siliconeresin (for example, JP-A-61-65808) and a skin protectant making use of asilicone/acrylic copolymer (for example, JP-A-2-262512) show highadhesion to the skin, but their use for the delicate skin is notpreferred because they must contain an organic solvent which causessevere skin irritation. In addition, they are released from the skineasily under the conditions inducing perspiration. Under dry conditions,on the contrary, they are highly adhesive to the skin, but use of areleasing agent which causes severe irritation is inevitable for theirrelease. Moreover, they have a problem such as insufficient skinprotecting effect, because a uniform film cannot be formed on thesurface such as skin which is uneven and does not stay still.

A foaming skin protectant (for example, JP-A-2002-145755) requiresemulsification of its effective ingredient so that it contains a largeamount of an emulsifier. In such a system, when a high-water-contentsubstance such as urine or exudate adheres to the skin,re-emulsification occurs. This facilitates peeling of the protectantfrom the skin and a film effective for a prolonged period cannot beformed. There is also a report on a skin cosmetic composition containinga non-hydrolytic block copolymer having linearpolysiloxane-polyoxyalkylene blocks as a repeating unit (JP-A-4-234307).This skin cosmetic composition contains a large amount of water so thatit stimulates the skin by giving a cold feeling thereto uponapplication. In addition to such an uncomfortable feeling, it has a highviscosity, which prevents uniform application thereof over a wide area.

There is also a report of a skin protectant containing a film formingagent, a hydrophobic powder and a volatile oil (JP-A-7-242528).According to this literature, a large amount of ethanol is used as asolvent for the film forming ingredient. When such a skin protectant isapplied to a delicate part of the skin such as rough skin, a smart painis induced by ethanol. It is therefore utterly unsuited for use.

Skin protectants capable of satisfying all of the following conditions,that is, high skin-protecting effect, long lasting effect, easyapplication with less irritation, and a comfortable feeling afterapplication have not yet been reported.

An object of the present invention is to provide a liquid skinprotective composition which is capable of protecting the skin fromchemical substances in the environment, or from aqueous irritants suchas body fluids, waste and exudates, is readily applicable with lessirritation and gives a good skin feel.

SUMMARY OF THE INVENTION

As a result of various investigations, the present inventor has foundthat a skin-protectant not only having an excellent skin-protectingeffect but also giving a good skin feel, causing less irritation andbeing applied readily can be obtained by using a block copolymer havinga linear polysiloxane-polyoxyalkylene block as a structural unit andhaving a specific HLB in combination with an oil, and by reducing thewater content.

In the present invention, there is thus provided a liquid skinprotective composition containing the below-described ingredients (A)and (B) and having a water content not more than 10 wt. %:

-   -   (A) a block copolymer having a linear        polysiloxane-polyoxyalkylene block as a structural unit and        having an HLB not more than 6;    -   (B) at least one kind of oil selected from mineral oils,        vegetable oils, animal oils, synthetic oils and        organopolysiloxanes other than the ingredient (A).

BEST MODE FOR CARRYING OUT THE INVENTION

Examples of the structure of the polyoxyalkylene block portion of theingredient (A) of the present invention, that is, the block copolymerhaving a linear polysiloxane-polyoxyalkylene block as a structural unitinclude polyoxyethylene, polyoxypropylene, and polyoxyethylenepolyoxypropylene. Of these, polyoxyethylene polyoxypropylene is morepreferred, because it permits uniform dissolution when a water repellentoil or volatile oil is added, and it has excellent low-temperaturestability.

As the ingredient (A), the linear polysiloxane-polyoxyalkylene blockpolymer as described in JP-A-4-234307 can be used. As the blockcopolymer serving as the ingredient (A), usable is a linearpolysiloxane-polyoxyalkylene block copolymer represented by thefollowing formula (1):(

Y(R₂SiO)_(a)R₂SiYo][AO]_(b)—)_(c)  (1)(wherein, R represents a monovalent hydrocarbon group free of analiphatic unsaturated group, A represents an alkylene group having from2 to 4 carbon atoms, b stands for a number of from 4 to 100 (preferablyfrom 10 to 90), b pieces of AO may be the same or different, c standsfor a number of from 2 to 40 (preferably from 2 to 20), a stands for anumber of from 4 to 100 (preferably from 5 to 40), and Y represents adivalent organic group bound to the adjacent silicon atom via acarbon-silicon bond and to a polyoxyalkylene block via an oxygen atom).

In particular, good results can be achieved by the use of ahigh-molecular-weight non-hydrolytic block copolymer having, as astructural unit, a linear polysiloxane-polyoxyalkylene block representedby the following formula (2):

(R″₂SiO)_(a+1)SiR″₂CH₂CR′HCH₂—O(AO)_(b)CH₂CR′HCH₂

_(c)  (2)(wherein, a stands for a number of from 4 to 100 (preferably, a numberof from 5 to 40), b stands for a number of from 4 to 100 (preferably, anumber of from 10 to 90), b pieces of AO may be the same or different, cstands for a number of from 2 to 40 (preferably, a number of from 2 to20), R′ represents a monovalent hydrocarbon group and R″ represents amonovalent hydrocarbon group) available by reacting a compoundrepresented by the following formula (A):HR″₂SiO(R″₂SiO)_(a)SiR″₂H  (A)(wherein, R″ represents a monovalent hydrocarbon group free of analiphatic unsaturated group, a stands for a number of from 4 to 100(preferably, a number of from 5 to 40) with a compound represented bythe following formula (B):

(wherein, R′ represents a monovalent hydrocarbon group, A represents analkylene group having from 2 to 4 carbon atoms, b stands for a number offrom 4 to 100 (preferably from 10 to 90), and b pieces of AO may be thesame or different).

Examples of R, R′ and R″ in the above-described formulas include groupsselected from alkyl groups (such as methyl, ethyl, propyl, isopropyl,butyl, pentyl, hexyl, octyl, decyl, dodecyl, octadecyl and eicosyl),aryl groups (such as phenyl and naphthyl), aralkyl groups (such asbenzyl and phenylethyl), tolyl group, xylyl group, and cyclohexyl group.In the above-described formulas, examples of the divalent organic grouprepresented by Y include —R′″—, —R′″—CO—, —R′″—NHCO—,—R′″—NHCONH—R″″—NHCO—, and —R′″—OOCNH—R″″—NHCO— (in which, R′″represents a divalent alkylene group such as ethylene, propylene orbutylene, R″″ represents a divalent alkylene group such as R′″ or adivalent arylene group such as —C₆H₄—, —C₆H₄—C₆H₄—, —C₆H₄—CH₂—C₆H₄—, or—C₆H₄—CH(CH₃)₂—C₆H₄—, with a phenylene group being preferred as R″″).More preferred examples of the divalent organic group include —CH₂CH₂—,—CH₂CH₂CH₂—, —CH₂CH₂CH₂CH₂—, —(CH₂)₂CO—, —(CH₂)₃NHCO—,—(CH₂)₃NHCONHC₆H₄NHCO— and —(CH₂)₃OOCNC₆H₄NHCO—. Of these, divalentalkylene groups are most preferred as Y, with —CH₂CH₂CH₂— beingespecially preferred.

The above-described non-hydrolytic copolymer can be prepared by reactinga polyoxyalkylene compound having a reactive terminal group with adihydrocarbylsiloxane liquid having a terminal group reactive with thereactive terminal group of this polyoxyalkylene compound.

The above-described polyoxyalkylene compounds include polyoxyethylene,polyoxypropylene, polyoxybutylene, and polyoxyethylene-oxypropylenemixture, of which the polyoxyethylene-oxypropylene mixture is morepreferred because it exhibits excellent stability when mixed.

The most preferred examples include block copolymers represented by thefollowing formula:

obtained by reacting a polyoxyalkylene compound having at each endthereof a CH₂═C(CH₃)—CH₂— group with a dimethyl-polysiloxane having ateach end thereof an HSi(CH₃)₂O-group. In the above-described formula, Merepresents a methyl group, A represents an alkylene group having from 2to 4 carbon atoms, b stands for a number of from 4 to 100 (preferablyfrom 10 to 90), b pieces of AO may be the same or different, a standsfor a number of from 4 to 100 (preferably from 5 to 40) and c stands fora number of from 2 to 40 (preferably from 2 to 20).

The block copolymer having the linear polysiloxane-polyoxyalkylene blockas a recurring unit must have an HLB not more than 6. When the blockcopolymer has an HLB not more than 6, it does not dissolve away byemulsification upon contact with water and has high water resistance,and at the same time, is effective for preventing permeation of anirritant through the skin, thus having a skin-protecting effect. The HLBis preferably not more than 4 from the standpoint of further improvingthe water resistance further. The HLB can be determined in the followingmanner.

After measurement of a cloud number A, the HLB is determined inaccordance with the below-described conversion formula. The term “cloudnumber A” as used herein means the number of mL of a 2% aqueous phenolsolution required for titration of a solution (when the liquid becomesturbid, the titration is terminated) which has been obtained bydissolving 0.5 g of a block copolymer having a linearpolysiloxane-polyoxyalkylene block as a recurring unit in 5 ml ofethanol, while maintaining the solution at 25° C.HLB=0.89×(cloud number A)+1.11

When the water content in the liquid skin protective composition isadjusted to not more than 10 wt. %, the ingredient (A) brings about suchan effect that the liquid skin protective composition is in the liquidform and spreads well when it is applied to the skin. The compositionthen thickens or turns into a gel, upon absorbing water evaporated fromthe skin or from the environment, whereby diffusion of the compositionover the skin is suppressed and its effect lasts long. In addition, thepolyoxyalkylene block and the skin surface interact with each other, forexample, by forming a hydrogen bond so that the composition has a higheradhesive power to the skin than an ordinary baby oil composed of liquidparaffin. It is not peeled off easily by friction so that it can protectthe skin from friction with cloth or the like. Moreover, since theingredient (A) is not solid, it does not bring discomfort caused byimpeding the movement of the skin. The ingredient (A) is less sticky andvery easily applicable to the skin. Even if the skin is wet, theingredient (A) can be applied without any difficulty and exhibits itsskin protective effect.

The content of the ingredient (A) in the liquid skin protectivecomposition is preferably from 3 to 50 wt. %, especially preferably from5 to 20 wt. %.

As the ingredient (B) of the present invention, at least one kind of oilselected from mineral oils, animal oils, vegetable oils, synthetic oilsand organopolysiloxanes other than the ingredient (A) can be used. Owingto their emollient effects for the skin, these oils have moisturizingeffects and are effective for preventing excessive drying of the skin.In addition, they can supplement skin lipid ingredients and serve toreinforce the skin barrier function. They improve the water repellencyand water resistance of the skin protectant. Moreover, owing to thelubricating effect, they can reduce the friction on the skin surface.

Specific examples include mineral oils such as mineral oil, liquidparaffin, liquid isoparaffin, naphthenic oil and petrolatum, vegetableoils such as olive oil, jojoba oil, cotton seed oil, peanut oil, castoroil, sunflower oil, coconut oil, almond oil, palm oil, safflower oil,corn oil, soybean oil, hydrogenated castor oil and hydrogenated palmoil; animal oils such as mink oil, turtle oil, guinea pig oil, squalane,beef tallow and lanolin; and synthetic oils such as poly-α-olefin oil,polyalkylene glycol oil, polybutene oil, and ester oils such asisopropyl myristate, dioctyl phthalate, diethylhexyl phthalate,octyldodecyl myristate, myristyl myristate, glycerin-tri-2-ethylhexyland triglyceride stearate. Examples of the organopolysiloxane includedimethylpolysiloxane, methylphenylpolysiloxane, silicone gum,alkyl-modified methylpolysiloxane, alkoxy-modified methylpolysiloxaneand amino-modified methylpolysiloxane. These oils may be used eithersingly or in combination of two or more of them.

The content of the ingredient (B) in the liquid skin protectivecomposition is preferably not less than 10 wt. %, more preferably from30 to 97 wt. %, especially preferably from 50 to 95 wt. %.

The ingredient (B) preferably contains (B-1) an oil ingredient having avolatility of not less than 0.2 mg/cm² hr and (B-2) an oil ingredienthaving a volatility not more than 0.1 mg/cm² hr. It is more preferredthat the ingredient (B-2) contains two kinds of oil having a volatilitynot more than 0.1 mg/cm² hr and mutual solubility not more than 10 wt.%.

The ingredient (B-1) has a low viscosity and easily spreads on the skinupon application so that it has an effect of reducing stickiness andimproving the skin feel. The ingredient (B-2) is useful for maintainingthe water resistance of the liquid skin protective composition of theinvention. The ingredient (B-1) preferably has a higher volatility,because the diffusion of the skin protective composition over the skincan be suppressed by the volatilization of the ingredient (B-1) and thecomposition is effective for longer hours and in addition, provides animproved skin feel. The volatility can be measured as a loss in weightper unit area and unit hour when 10 g of an oil is put into a Petri dishhaving an inner diameter of 85 mm and depth of 11 mm and allowed tostand at 25° C. under atmospheric pressure. The volatility of theingredient (B-1) is preferably from 0.2 to 50 mg/cm² hr, more preferablyfrom 0.3 to 20 mg/cm² hr, especially preferably from 0.5 to 5 mg/cm² hr.

The ingredient (B-2) is preferably added in order to keep waterresistance and lubrication of the skin protectant of the invention evenafter evaporation of the ingredient (B-2) when the protectant is appliedto the skin. The lower the volatility of the ingredient (B-2) is thelonger the skin-protecting effect is maintained. The volatility at 25°C. is preferably not more than 0.1 mg/cm² hr, more preferably not morethan 0.03 mg/cm² hr.

Examples of the ingredient (B-1) include volatile organopolysiloxanesand volatile liquid isoparaffin. The volatile organopolysiloxanesinclude hexamethyldisiloxane, octamethyltrisiloxane,decamethyltetrasiloxane, octamethylcyclotetrasiloxane anddecamethylcyclopentasiloxane. Use of cyclic methylcyclopolysiloxanessuch as decamethylcyclopentasiloxane is preferred in consideration ofless irritation and good skin feel when a composition containing it issprayed. The content of the ingredient (B-1) in the liquid skinprotective composition is not less than 10 wt. %, more preferably from30 to 80 wt. %.

Preferred ingredient (B-2) includes at least one selected from liquidparaffin, liquid isoparaffin, squalane, isopropyl myristate, fatty acidtriglyceride, decamethylcyclopentasiloxane, methylpolysiloxane,methylcyclopolysiloxane and dimethylpolysiloxane. Of these, at least oneselected from liquid paraffin, liquid isoparaffin, squalane,methylcyclopolysiloxane and dimethylpolysiloxane is more preferred.

The ingredient (B-2) preferably contains two kinds of oil having amutual solubility not more than 10 wt. %. At a low mutual solubility,when the composition is applied to the skin, non-sticky feel remainslong after evaporation of the ingredient (B-1), which brings about ahigh lubrication effect. The term “mutual solubility” means a lowerconcentration of the concentrations of one of the two kinds of oil (wt.% in the mixture) at the time when the mixture obtained by adding understirring one of the two kinds of oil to the other turns from transparentto turbid. The mutual solubility at 25° C. is preferably not more than10 wt. %, more preferably not more than 3 wt. %, especially preferablynot more than 1 wt. %. It is preferred to use such two kinds of oil at amixing ratio (wt/wt) of from 1/4 to 4/1, more preferably from 1/2 to2/1. Examples of such a combination include a combination of ahydrocarbon oil having a relatively large molecular weight such asliquid paraffin or squalane and an organopolysiloxane such asdimethylpolysiloxane. These ingredients can be added stably by the useof the above-described volatile organopolysiloxane or volatile liquidisoparaffin. When the volatile ingredient evaporates, phase separationof these ingredients occur, which leads to exhibition of effects.

In order to attain high lubrication, the viscosity at 25° C. of thehydrocarbon oil is preferably not less than 20 mPa·s and the viscosityat 25° C. of the organopolysiloxane is preferably not less than 10mPa·s. The viscosity at 25° C. of the hydrocarbon oil is more preferablynot less than 40 mPa·s and the viscosity at 25° C. of theorganopolysiloxane is more preferably not less than 20 mPa·s.

The content of the ingredient (B-2) in the liquid skin protectivecomposition is preferably not less than 10 wt. %, more preferably from20 to 80 wt. %, especially preferably from 30 to 60 wt. %.

The water content in the liquid skin protective composition of theinvention is not more than 10 wt. %, preferably not more than 3 wt. %,more preferably not more than 1 wt. %. When the water content in thecomposition is not more than 10 wt. %, the viscosity of the wholecomposition lowers, facilitating application of the composition. In thiscase, addition of a surfactant or emulsifier is not necessary and thecomposition does not melt away over the skin by emulsification so thatit has improved water resistance and becomes less irritant to the skin.Application of water to an area of the skin sensitive to stimulation isnot preferred, because water gives a cold feel to the skin owing to aconsiderably large latent heat of evaporation. When the water content isnot more than 3 wt. %, a cold feel given to the skin is very weak. At awater content not more than 1 wt. %, the cold feel approaches zero. Inaddition, the composition having a smaller water content is effectivefor reducing the friction on the skin.

The liquid skin protective composition of the invention is preferably inthe liquid form and has a low viscosity at normal temperature (25° C.).The viscosity at 25° C. is preferably not more than 70 mPa·s, morepreferably not more than 50 mPa·s, especially not more than 30 mPa·s.When the composition has a low viscosity, it can be spread over the skinreadily upon application. It can also be applied over a wide area byspraying.

In the liquid skin protective composition of the present invention, theingredient (A) and ingredient (B) are included at a weight ratio (A)/(B)of from 3/100 to 60/100, more preferably from 3/100 to 30/100,especially preferably from 5/100 to 15/100. When the ratio is not lessthan 3/100, the resulting composition has an improved skin protectingeffect. When the ratio is not more than 60/100, on the other hand, theresulting composition has a reduced viscosity, has improvedapplicability and provides a good skin feel after application.

The content of the monovalent alcohol having from 1 to 4 carbon atoms inthe liquid skin protective composition of the present invention ispreferably not more than 10 wt. %. Examples of the monovalent alcoholhaving from 1 to 4 carbon atoms include ethanol, methanol, isopropanol,1-propanol and butyl alcohol. The content of the monovalent alcoholhaving from 1 to 4 carbon atoms is more preferably not more than 3 wt.%, especially preferably not more than 1 wt. %. When the content of thevolatile alcohol in the composition of the present invention is not morethan 10 wt. %, the composition is mild to the skin, for example, thecomposition does not smart, and moreover, continuous use of thecomposition does not roughen the skin even if it is applied to a verydelicate area of the skin, for example, buttocks or the skin around astoma or a wound. Application of the composition of the presentinvention to these delicate areas is mainy intended in the presentinvention. In particular, when the content is not more than 3 wt. %, anirritating feeling given to the skin upon application lowers further andin addition, a cold feeling which is caused by the latent heat ofevaporation of a volatile ingredient becomes less. The composition isalmost free from giving an irritating feeling or a cold feeling uponapplication particularly when the content is not more than 1 wt. %.

The liquid skin protective composition of the present invention mayfurther contain an anti-inflammatory agent. Incorporation of theanti-inflammatory agent enables to prevent occurrence of inflammationsuch as diaper rash, redness, contact-type dermatitis or the like. Evenif the content of the anti-inflammatory agent is small, it remains longon the skin and is expected to provide a high effect when incorporatedin the liquid skin protective composition. Although no particularlimitation is imposed on the anti-inflammatory agent, examples includeguaiazulene, allantoin, soybean lecithin, anethole, linalyl acetate,terpinyl acetate, glycyrrhetic acid, stearyl glycyrrhetinate,dipotassium glycyrrhetinate, and hydrocortisone acetate.Anti-inflammatory agents having a high lipophilic property such asguaiazulene are preferred from the viewpoint of mixing with the otheringredients. Its content in the liquid skin protective composition isnot more than 1 wt. %, preferably from 0.0001 to 0.2 wt. %, morepreferably from 0.0005 to 0.1 wt. %.

Since the liquid skin protective composition of the present invention isapplied to an area which may probably contact with microbe causing skininflammation (such microbe may be called “infecting organisms”) in fecesor wound exudates, occurrence of infectious diseases such as urinarytract infection due to such infecting organisms can be prevented byincorporating an antimicrobial agent in the composition. Although noparticular limitation is imposed on the antimicrobial agent, thosecausing as less skin irritation as possible are preferred becauseantimicrobial agents are known to cause skin irritation. In addition,those having a high lipophilic property are preferred from thestandpoint of stability upon mixing. Specific examples includeisopropylmethylphenol, triclosan, benzalkonium chloride, benzethoniumchloride and chlorhexidine gluconate. Its content, as an effectiveingredient, in the composition of the present invention is from 0.0001to 1 wt. %, preferably from 0.0005 to 0.2 wt. %, more preferably from0.001 to 0.05 wt. %.

The liquid skin protective composition of the present invention ispreferably free of an inorganic powder such as pigment. When thecomposition does not contain an inorganic powder, the resulting liquidskin protective composition can be released from the skin by washing,has high lubrication effect and does not clog a nozzle when used in theform of a spray.

To the liquid skin protective composition of the present invention maybe added, as necessary, a humectant, an antioxidant, a blood circulationpromoter, an antiseptic, a deodorant, an ultraviolet absorber, acolorant, a pigment and the like to an extent, in term of both quantityand quality, not impairing the advantages of the present invention.

The liquid skin protective composition of the present invention can beprepared in a manner known per se in the art by adding to theabove-described essential ingredients the above-described optionalingredients, if necessary. These optional ingredients can be added tothe composition in an amount not more than 30 wt. %.

The liquid skin protective composition of the present invention can beprovided in any form of liquid, mist and foam. It can be used, forexample, in the form of an aerosol spray, pump spray, pump bottle ortube, or absorbent cotton, paper or cloth impregnated with it. A mistspray or nonwoven cloth impregnated with the composition is desiredbecause it can be applied to a wide area without direct contact.Application of the composition by spray does not need direct contactwith the affected area so that hand washing after use can be omitted.Use of a pump spray container without a propellant such as liquefied gasor carbon dioxide gas is most preferred, because stimulation or a coldfeeling to the skin which will otherwise be brought by the evaporationheat of the propellant can be reduced. The composition can be appliedreadily to a wide area by using a nonwoven cloth impregnated with thecomposition and when the composition is applied in such a manner, therewill be no possibility of staining floor caused by dripping orscattering of the composition.

EXAMPLES Examples 1 to 7, Comparative Examples 1 to 4

Liquid skin protective compositions of Examples 1 to 7 and ComparativeExamples 1 to 4 having compositions (on a weight basis) as shown inTables 1 and 2 were prepared in a manner known per se in the art inaccordance with the below-described formulations.

Evaluation Method

[Viscosity]

Viscosity was measured using a Brookfield type viscometer at 25° C.

[Evaluation of Skin Protecting Effect]

The color of the skin was measured using a calorimeter (“ND300A”,product of Nippon Denshoku Industries Co., Ltd., spectrophotometer) andthe liquid skin protective composition was applied to the site of theskin. A 0.5% aqueous solution of Blue No. 1 was then brought intocontact for 5 minutes with the skin to which the liquid skin protectivecomposition had been applied. After the liquid skin protectivecomposition was washed away, the color of the skin was measured by thecalorimeter. A color difference (ΔE) between the skin after thetreatment, and the skin before application of the liquid skin protectivecomposition and before contact with the colorant solution was determinedin accordance with JIS Z8730. How much coloring of the skin wasprevented compared with the color difference (ΔE₀) when the colorantsolution was brought into contact with a site to which nothing had beenapplied can be calculated as a skin protecting effect (%) from thebelow-described equation.Skin protecting effect (%)=(ΔE₀−ΔE)/ΔE₀×100

As the percentage approaches 100%, a skin-protecting effect becomeshigher and better.

[Evaluation of Friction Coefficient]

The liquid skin protective composition was applied with a coating weightof 3 mg/cm² to a polyurethane foam (“OK mat”, product of Okamoto Co.,Ltd.) used as a model skin. After it was allowed to stand at roomtemperature for not less than 2 hours, friction between the model skinand a cotton fabric (Kanakin No. 3), that is, a standard sample made byJapanese Standards Association was measured using a KES surface frictionproperty tester (product of Kato Tech Co., Ltd.), whereby a frictioncoefficient was obtained.

(Evaluation Using a Pump-Type Spray Container Under Natural Pressure)

The liquid skin protective composition of each of Examples 1 to 6 andComparative Examples 1 to 4 was filled in a pump type spray containercapable of spraying the composition in the form of a mist and a panel of13 caregivers applied the composition to the buttock skin of bedriddencare receivers after their consent. The applicability and skinprotecting effect were evaluated by the organoleptic evaluation of thecaregivers, while the irritating feeling and skin feel were evaluatedbased on the results of interview with the care receivers. Thus, theperformances of the composition were evaluated.

The liquid skin protective composition was sprayed through a pump typespray container in an amount of about 0.2 g per one spray and it wassprayed about four times to the buttock skin.

(Evaluation Using a Sheet Obtained by Impregnating a Nonwoven Fabricwith the Skin Protective Composition)

A cotton nonwoven spunlace (“Cotton Ace”, product of UNITIKA Ltd., basicweight: 40 g) was impregnated with the liquid skin protectivecomposition of Example 7. The amount of the liquid skin protectivecomposition was 150% of the weight of the nonwoven fabric. Each sheethad a size of 150 mm×190 mm. One box was filled with 40 sheets.

Evaluation results are shown in Tables 1 and 2. The number in the columnof the evaluation results means the number of persons. TABLE 1 Examples1 2 3 4 5 6 7 Ingredi- Block copolymer having a linear HLB = 1 ¹⁾ 10 510 10 ent (A) polysiloxane-polyoxyalkylene block HLB = 3 ²⁾ 10 35 20 asa recurring unit HLB = 7 ³⁾ Ingredi- Methyl polysiloxane 1 ⁴⁾ 45 ent (B)Methylpolysiloxane 2 ⁵⁾ 20 20 Liquid paraffin 1 ⁶⁾ 20 Liquid paraffin 2⁷⁾ 20 20 Squalane 25 Safflower oil 46 Isopropyl myristate ⁸⁾ 54 Fattyacid triglyceride ⁹⁾ 25 Decamethylcyclopentasiloxane ¹⁰⁾ 36 50 30 50 50Liquid isoparaffin ¹¹⁾ 40 Organic silicone resin/octamethylcyclopolysiloxane (weight ratio 50/50) ¹²⁾ Methylpolysiloxane1.5cs ¹³⁾ 40 Methylphenylsilicone ¹⁴⁾ Water 4.99 Ethanol 3.979Dipotassium glycyrrhizinate ¹⁵⁾ 0.01 α-Tocopherol acetate 0.2Benzalkonium chloride ¹⁶⁾ 0.001 Viscosity (mPa · s) 12 26 11 62 30 20 20Skin protecting effect (%) 88 91 82 89 83 89 89 Friction coefficient 4.65.4 5.8 4.8 6.1 3.1 3.1 Applicability Good 11 10 12 8 12 12 10 Poor 2 31 5 1 1 3 Irritation upon application Absent 13 8 13 12 7 13 12 Present0 5 0 1 6 0 1 Skin feel after application Good 12 9 11 7 10 12 12 Poor 14 2 6 3 1 1 Skin protecting effect Present 9 9 6 11 10 10 9 Slightly 4 36 2 2 3 4 present None 0 1 1 0 1 0 0

TABLE 2 Comparative Examples 1 2 3 4 Ingredi- Block copolymer having alinear HLB = 1 ¹⁾ ent (A) polysiloxane-polyoxyalkylene block as a HLB =3 ²⁾ 10 recurring unit HLB = 7 ³⁾ 10 Ingredi- Methyl polysiloxane 1 ⁴⁾35 ent (B) Methylpolysiloxane 2 ⁵⁾ Liquid paraffin 1 ⁶⁾ Liquid paraffin2 ⁷⁾ Squalane Safflower oil Isopropyl myristate ⁸⁾ 54 60 Fatty acidtriglyceride ⁹⁾ Decamethylcyclopentasiloxane ¹⁰⁾ 36 40 Liquidisoparaffin ¹¹⁾ 40 Organic silicone resin/ 10octamethylcyclopolysiloxane (weight ratio 50/50) ¹²⁾ Methylpolysiloxane1.5cs ¹³⁾ 85 Methylphenylsilicone ¹⁴⁾ 5 Water 14.99 Ethanol Dipotassiumglycyrrhizinate ¹⁵⁾ 0.01 α-Tocopherol acetate Benzalkonium chloride ¹⁶⁾Viscosity (mPa · s) 12 6 138 8 Skin protecting effect (%) 10 17 70 23Friction coefficient 7.3 6.3 8.3 6.5 Applicability Good 11 12 0 10 Poor2 1 13 3 Irritation upon application Absent 11 12 4 8 Present 2 1 9 5Skin feel after application Good 3 11 2 3 Poor 10 2 11 10 Skinprotecting effect Present 1 2 4 4 Slightly 4 6 6 5 present None 8 5 3 4In Tables 1 and 2:

-   1): “SIL-WET FZ-2203”, trade name; product of Nippon Unicar Co.,    Ltd. Structural unit:-   2) “SIL-WET FZ-2207”, trade name; product of Nippon Unicar Co., Ltd.    Structural unit:-   3) “SIL-WET FZ-2222”, trade name; product of Nippon Unicar Co., Ltd.    Structural unit:-   4) “SH200C 10cs”, trade name; product of Dow Corning Toray Silicone    Co., Ltd.-   5) “SH200C 20cs”, trade name; product of Dow Corning Toray Silicone    Co., Ltd.-   6) “Hicall K-230”, trade name; product of Kaneda Corporation.-   7) “Hicall K-350”, trade name; product of Kaneda Corporation.-   8) “EXCEPARL IPM”, trade name; product of Kao Corporation-   9) “COCONARD MT”, trade name; product of Kao Corporation-   10) “SH245”, trade name; product of Dow Corning Toray Silicone Co.,    Ltd.-   11) “IP Solvent 1620”, trade name; product of Idemitsu Petrochemical    Co., Ltd.-   12) “KF7312F”, trade name; product of Shin-etsu Chemical Co., Ltd.-   13) “SH200C 1.5cs”, trade name; product of Dow Corning Toray    Silicone-   14) “KF56”, trade name; product of Shin-etsu Chemical Co., Ltd.-   15) “CO glychinol”, trade name; product of Maruzen Pharmaceuticals    Co., Ltd.-   16) “Nissan Cation M2-100”, trade name; product of NOF Corporation

The results shown in Tables 1 and 2 indicate that the compositions ofExamples 1 to 6 are sprayed well at room temperature, the compositionsof 1 to 7 do not give an irritating feeling upon application, give avery good skin feel with smoothness and can protect the skin veryeffectively. On the other hand, the composition of Comparative Example 1exhibits a considerably reduced skin-protecting effect. The compositionof Comparative Example 2 exhibits good applicability and skin feel, butexhibits only a low skin-protecting effect. The composition ofComparative Example 3 cannot be sprayed well and in addition, cannot beapplied to the skin easily and gives an uncomfortable skin feel.Moreover, its skin-protecting effect is very low. The composition ofComparative Example 4 leaves a taut feeling and stickiness on the skinafter application, does not give a good skin feel, and does not bringabout an apparent skin-protecting effect.

INDUSTRIAL APPLICABILITY

The liquid skin protective composition of the present invention has ahigh skin-protecting effect, can be applied to the skin easily, does notcause a skin irritation, and gives a good skin feel. It can therefore beused for protecting the skin, particularly, a diapered site of babies orincontinent patients, the skin around stoma, and the skin around woundwith exudates.

1. A liquid skin protective composition comprising the below-describedingredients (A) and (B) and having a water content not more than 10 wt.%: (A) a block copolymer having a linear polysiloxane-polyoxyalkyleneblock as a structural unit and having an HLB not more than 6, (B) atleast one kind of oil selected from mineral oils, vegetable oils, animaloils, synthetic oils and organopolysiloxanes other than the ingredient(A).
 2. The liquid skin protective composition of claim 1, wherein theingredient A is a block copolymer represented by the following formula(1):(

Y(R₂SiO)_(a)R₂SiYO][AO]_(b)—)_(c)  (1) (wherein, R represents amonovalent hydrocarbon group free of an aliphatic unsaturated group, Arepresents an alkylene group having from 2 to 4 carbon atoms, b standsfor a number of from 4 to 100, b pieces of AO may be the same ordifferent, c stands for a number of from 2 to 40, a stands for a numberof from 4 to 100, and Y represents a divalent organic group bound to theadjacent silicon atom via a carbon-silicon bonded and to thepolyoxyalkylene block via an oxygen atom).
 3. The liquid skin protectivecomposition of claim 1 or 2, wherein the siloxane blocks each has anaverage molecular weight of from 500 to 10,000, the polyoxyalkyleneblocks each has an average molecular weight of from 300 to 10,000, thesiloxane blocks constitute from 10 to 90 wt. % of the copolymer, and theblock copolymer has an average molecular weight of at least 3,000. 4.The liquid skin protective composition of any one of claims 1 to 3,wherein the viscosity at 25° C. is not more than 70 mPa·s.
 5. The liquidskin protective composition of any one of claims 1 to 4, wherein theingredient (A) and the ingredient (B) are included at a (A)/(B) weightratio of from 3/10 to 60/100.
 6. The liquid skin protective compositionof any one of claims 1 to 5, wherein the content of the ingredient (A)is from 3 to 50 wt. %.
 7. The liquid skin protective composition of anyone of claims 1 to 6, wherein the content of the ingredient (B) is notless than 10 wt. %.
 8. The liquid skin protective composition of any oneof claims 1 to 7, wherein the ingredient (B) is at least one selectedfrom liquid paraffin, liquid isoparaffin, methylcyclopolysiloxane anddimethylpolysiloxane.
 9. The liquid skin protective composition of anyone of claims 1 to 8, wherein the ingredient (B) comprises (B-1) an oilingredient having a volatility of not less than 0.2 mg/cm² hr and (B-2)an oil ingredient having a volatility not more than 0.1 mg/cm² hr. 10.The liquid skin protective composition of claim 9, wherein theingredient (B-1) comprising two kinds of oil having a volatility notmore than 0.1 mg/cm² hr and a mutual solubility not more than 10 wt. %.11. A method of applying a liquid skin protective composition of claim 1by spraying.
 12. A method of applying a liquid skin protectivecomposition of claim 1 by using a material impregnated with thecomposition.
 13. Use of a liquid skin protective composition of claim 1to protect the skin.